PTL 1 discloses a color conversion coefficient calculator. The color conversion coefficient calculator calculates a color conversion coefficient for converting a first color signal made up of a plurality of color signals into a second color signal made up of a plurality of color signals. The color conversion coefficient calculator includes color conversion coefficient calculation means, correction coefficient calculation means, and coefficient correction means. The color conversion coefficient calculation means calculates a color conversion coefficient for converting a first spectral characteristic that characterizes the first color signal in a standard fashion into a second spectral characteristic that characterizes the second color signal. The correction coefficient calculation means calculates a correction coefficient for approximating a base color signal serving as a first color signal that corresponds to a plurality of base colors to a reference color signal that is obtained based on the first spectral characteristic in accordance with the plurality of base colors. The coefficient correction means corrects the color conversion coefficient by using the correction coefficient. The base color signal is a first color signal that is obtained by imaging color patches of a plurality of colors that correspond to the plurality of base colors. The reference color signal is a color signal that is obtained based on spectral characteristics of the color patches of the plurality of colors and the first spectral characteristic. Each of the color patches is a color patch that emits light in a specified narrow band.
By doing this, the color conversion coefficient calculator described above can easily realize high-precision color conversion processing according to a difference between individuals in addition to a difference between models.